Up to now, radiation images such as X-ray images have been widely used in diagnosing sicknesses at medical institutions. In particular, radiation images obtained by using intensifying screen and films have achieved high sensitivity and high quality over the long history, and as a result, they are still being used worldwide as highly reliable systems which also have excellent cost-performance. In recent years, computed radiography using stimulable phosphor panels as radiation image conversion panels has also been commercialized and improvements in terms of high sensitivity and image quality are being continuously made.
The stimulable phosphor panel referred to above is one in which radiation rays which have been transmitted through a subject is accumulated, and the accumulated rays are emitted as stimulated luminescence by radiation of excitation light with an intensity in accordance with the amount of rays. The stimulable phosphor panel has a structure in which a stimulable phosphor layer is formed on a prescribed substrate. One example of a manufacturing method for this type of stimulable phosphor panel is disclosed in Patent Document 1. In the manufacturing method described in Patent Document 1, a stimulable phosphor panel is manufactured by forming a stimulable phosphor layer on a prescribed substrate using a known vapor-phase deposition method, and then subjecting the stimulable phosphor panel to heat processing (see paragraph 0034 and 0035).
It is to be noted that in the case where the foregoing stimulable phosphor panel is used as the radiation image conversion panel, a stimulable phosphor panel is generally interposed between two films made of resin and the side edges of the films are heated to fuse and thus the phosphor panel is sealed between the films. If the film is not heated and fused at a suitable temperature, the desired space will not be formed between the stimulable phosphor layer of the stimulable phosphor panel and the film (that is, the stimulable phosphor layer and the film are brought in close contact but the space is narrower than necessary) and there is the possibility that image unevenness or linear noise will occur on the radiation image.
[Patent Document 1] Japanese Patent Application Laid-Open No. 2003-279696